9 months and having awful time

DD has always fed really well, slept really well etc. I went back to work last week which seems to have coincided with a growth spurt. On the days I work I only feed her in the morning and in the evenings/overnight. She nurses almost all evening and it's still not enough. She has fed repeatedly this evening and has just drained a load of cows milk.

I used to have an abundant supply of milk but it just doesn't seem to be enough. Expressing is not increasing it. I don't know what to do.

I would/do let DD have unlimited access when I'm at home (and I'm out 9-6 Mon-Fri) which means feeding at least every 3 hours. During the day she is given 1 3oz EBM, 3 meals, 1 snack of a slice of toast plus extra fruit snacks to distract her until I get in. Saying that 2x3oz is what she's probably naturally take, but it's less expressing for me.

By 9 months, supply is steadier and also a bit more stubborn to increase so it just may take longer to see changes. I would express same time each day. plus squeeze in extra ones if you're worried. If it's just a spurt, then her intake will decrease again afterwards, so it's not like you need to sustain an increased supply.

I express once at work now and get 5/6oz.

Also DD would drink loads during the day if we let her. So she's just not offered it.